This invention relates to window frame rubber moldings for an automobile. The term "window frame rubber moldings" as used herein means the rubber strips which are fitted to the edges of such stationary window glasses as a windscreen and a rear window and quarter windows in an automobile so as to protect the automobile interior against wind, rain, dust, noise, cold, and heat prevailing in the ambience.
In the present specification, this invention will be described with reference typically to a main body 5 of a window frame rubber molding which, as illustrated in FIGS. 1 and 2, incorporates therein a flange retaining groove 1 and a glass retaining groove 3 opening in mutually opposite directions and possesses an approximately S-shaped cross section. The window frame rubber moldings contemplated by the present invention are not limited to this construction.
The main body 5 of a window frame rubber molding is generally produced by extrusion molding with a rubber compound such as ethylene-propylene rubbers (EPDM, EPM) or chloroprene rubber (CR) or an elastomer material such as thermoplastic elastomers.
With the main body 5 of the window frame rubber molding formed as described above, it has been customary for a given glass sheet G to be secured to an automobile body by causing the main body 5 to be joined to the glass sheet G with the glass retaining groove 3 taking fast hold of the edge of the glass sheet G and then causing the flange retaining groove 1 to be fitted on an automobile body flange 11 with the opening side of the flange retaining groove 1 spread out by a pull at a groove spreading cord 7 fixed in advance in the flange retaining groove 1 (FIG. 1).
Owing partly, if not wholly, to the increasingly prevailing practice of spraying an antifreeze agent (common salts in most cases) on road surfaces during the winter season, the automobile body flange 11 inserted in the flange retaining groove 1 has been urged to possess higher rustproofing properties than ever.
As a solution, there may be conceived an idea of filling the bottom part of the flange retaining groove with a sealant made of a macromolecular material incorporating therein a rustproofing agent in combination with a highly absorbent polymer as disclosed in the specification of Japanese Utility Model Application Disclosure SHO 62(1987)-68,850, for example. In the case of the window frame rubber molding of the aforementioned type, however, this idea is substantially impracticable because the sealant cannot be easily extruded simultaneously in a desired part and the die head to be used for the extrusion gains immensely in intricacy.
There may be conceived another idea of filing the bottom part with a nondrying sealant after the main body has been vulcanization molded. This idea is substantially infeasible because when the cord inserted in the flange retaining groove is pulled during the attachment of the main body of window frame rubber molding to the automobile body, the sealant adheres to the cord and impairs the efficiency of the work of attachment in a large measure.